A porous and chemical stable Co(II)-based metal-organic framework for the selective fluorescence sensing of Fe3+and tetracycline

As a novel class of sensing materials, metal -organic frameworks (MOFs) have been developed as promising candidates for application of efficient sensing. Herein, a stable Co(II)-based MOF (noted as Co-MOF) was selected as the fluorescent sensor for the exploration of its sensing ability towards metal ions and antibiotic molecules. The fluorescence sensing experiments suggested that Co-MOF exhibited selective and sensitive sensing of Fe3+ and tetracycline among other ions and antibiotic molecules. The Stern-Volmer quenching constant (Ksv) of Fe3+ and tetracycline (TC) were determined to be 1.38 x 104 M-1 and 1.77 x 104 M-1, respectively, while the limit of detection values were calculated as 6.04 mu M for Fe3+ and 4.71 mu M for tetracycline. Additionally, the sensing mechanism of Co-MOF was further explored by UV-vis absorption spectroscopy and density functional theory (DFT) calculation, indicating that the fluorescence quenching is attributed to synergistic effect of photoinduced electron transfer (PET) and energy competition.